HARVEY, Ill. (CBS) — Two adults and two children were still being held hostage in south suburban Harvey early Wednesday, nearly 18 hours after the standoff began when two police officers were shot by the suspects.

Four other children — two 1-year-olds, a 2-year-old, and a 12-year-old — who had been held captive have been safely rescued from the home, and taken to a hospital for observation.

“Everything’s fine, as it relates to their physical health. They were taken to a nearby hospital for observation. I think it’s more trauma, mentally, than it is physical,” Harvey spokesman Sean Howard said.

As of 6:30 a.m. Wednesday, two suspects were still barricaded inside a home at 147th Street (Sibley Boulevard) and Robey Avenue, holding two adults and two children hostage.

Nearby Rosa Parks Middle School was supposed to have its first day of class on Wednesday, but has been closed for the day due to the hostage situation.

Thornton Township High School, located a mile-and-a-half away, was open Wednesday, but students have been advised to avoid the scene of the standoff, and should use 150th Street to get to the school, rather than 147th Street/Sibley Boulevard. Extra buses also were made available to get Thornton students to school safe.

Sibley has been closed to traffic between Wood Street and Dixie Highway.

As the officers arrived at the scene they spotted a suspect who aimed a gun at them and opened fire. One officer was shot multiple times in the arm, and the other suffered a graze wound. The two suspects then barricaded themselves inside a home at 147th and Robey, and took eight people hostage — two adults and six children.

The officer who was more seriously hurt – Darnell Keel, a 15-year veteran officer – suffered a broken arm and was treated at Advocate Christ Medical Center in Oak Lawn before he was sent home Tuesday night.

“The longer they’re able to keep them negotiating, the longer they’re able to keep them engaged, the better chance that they have to have a successful outcome to this,” he said. “Quite frankly, I’m surprised that they’re still inside the house right now, given the amount of time that’s passed. It usually doesn’t last this long, but the fact that they’re still there and they still have an open line of communication, I think, is a positive.”

Negotiators from the county and state have been communicating with at least one of the offenders. Harvey Police said they believe the negotiation will last a while and they are not familiar with the offenders.

At least 19 police departments and approximately 200 officers were involved in the standoff.

“I’m proud of the way our team of professionals are handling the negotiation process and again, we pray for a very peaceful resolve,” said Harvey Mayor Eric Kellogg.